Texas Instruments PLUS TI-89 - Manual (Page 465)

448 Appendix A: Functions and Instructions
8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 448 of 132
factor( rationalNumber ) returns the rational
number factored into primes. For composite
numbers, the computing time grows
exponentially with the number of digits in the
second-largest factor. For example, factoring
a 30-digit integer could take more than a day,
and factoring a 100-digit number could take
more than a century.
Note: To stop (break) a computation, press
´.
If you merely want to determine if a number
is prime, use
isPrime() instead. It is much
faster, particularly if rationalNumber is not
prime and if the second-largest factor has
more than five digits.
factor(152417172689) ¸
123457ø1234577
isPrime(152417172689) ¸false
Fill MATH/Matrix menu
Fill expression, matrixVar ⇒ matrix
Replaces each element in variable matrixVar
with expression .
matrixVar must already exist.
[1,2;3,4]! amatrx ¸ [
1 2
3 4
]
Fill 1.01,amatrx ¸ Done
amatrx ¸ [
1.01 1.01
1.01 1.01
]
Fill expression, listVar ⇒ list
Replaces each element in variable listVar
with expression .
listVar must already exist.
{1,2,3,4,5}! alist ¸
{1 2 3 4 5}
Fill 1.01,alist ¸ Done
alist ¸
{1.01 1.01 1.01 1.01 1.01}
floor() MATH/Number menu
floor( expression ) ⇒ integer
Returns the greatest integer that is  the
argument. This function is identical to int() .
The argument can be a real or a complex
number.
floor(л 2.14) ¸ л 3.
floor( list1 ) ⇒ list
floor( matrix1 ) ⇒
matrix
Returns a list or matrix of the floor of each
element.
Note: See also ceiling() and int() .
floor({3/2,0,л 5.3}) ¸
{1 0 л 6.}
floor([1.2,3.4;2.5,4.8]) ¸
[
1. 3.
2. 4.
]
fMax() MATH/Calculus menu
fMax( expression, var ) ⇒
Boolean expression
Returns a Boolean expression specifying
candidate values of
var that maximize
expression or locate its least upper bound.
fMax(1ì (xì a)^2ì (xì b)^2,x) ¸
x =
a+b
2
fMax(.5x^3ì xì 2,x) ¸ x = ˆ